Head-to-head weight-management evidence

Tirzepatide vs semaglutide: what the evidence shows

Name: Tirzepatide vs Semaglutide | Weight Loss Evidence & Safety
Creator: TYZEPA
Published: 2026-09-24

SURMOUNT-5 provides a direct comparison in adults without diabetes. Here is what the study found, what it did not prove, and how product identity and individual safety still shape treatment decisions.

Published 24 September 2026Last fact checked 24 September 20266 cited sources

For the full overview of uses, safety, product differences and verification questions, start with our tirzepatide in Pakistan patient guide.

What is the difference between tirzepatide and semaglutide?

Semaglutide activates the glucagon-like peptide-1 (GLP-1) receptor. Tirzepatide activates both the glucose-dependent insulinotropic polypeptide (GIP) receptor and the GLP-1 receptor. Both can reduce appetite and energy intake, slow gastric emptying and improve glucose-related measures. Tirzepatide’s additional GIP activity is a pharmacologic difference; it does not by itself predict how much weight an individual will lose or which medicine that person will tolerate better.

Brand names can cause confusion. In current United States labelling, Zepbound is tirzepatide for chronic weight management and certain adults with obesity-related obstructive sleep apnoea, while Mounjaro is tirzepatide labelled for type 2 diabetes. Wegovy is semaglutide labelled for chronic weight management and additional specified indications, while Ozempic is semaglutide labelled for type 2 diabetes and specified cardiovascular and kidney risk reduction.³⁴⁵⁶

Approved uses and available presentations may differ in Pakistan. Patients should follow the information for the exact locally supplied product and their prescriber’s advice.

SURMOUNT-5: the direct comparison

SURMOUNT-5 was a 72-week randomized, open-label trial in 751 adults with obesity, or overweight plus a weight-related complication, who did not have type 2 diabetes.¹² It compared the maximum tolerated dose of tirzepatide, 10 mg or 15 mg weekly, with semaglutide, 1.7 mg or 2.4 mg weekly. Both groups also received lifestyle counselling.

At week 72, the least-squares mean change in body weight was −20.2% with tirzepatide and −13.7% with semaglutide. Mean waist circumference changed by −18.4 cm and −13.0 cm, respectively. Tirzepatide also produced higher proportions of participants reaching weight-loss thresholds of at least 10%, 15%, 20% and 25%.¹

These are group averages from a controlled trial. They are not a promise of an individual result. A person may lose more, less or no weight, and treatment may be stopped because of side effects, contraindications, pregnancy, cost, availability or a change in clinical priorities.

The results and limits side by side

Question	Tirzepatide	Semaglutide
Receptor activity	GIP and GLP-1 receptor agonist	GLP-1 receptor agonist
SURMOUNT-5 weekly doses	Maximum tolerated 10 mg or 15 mg	Maximum tolerated 1.7 mg or 2.4 mg
Mean weight change at 72 weeks	−20.2%	−13.7%
Mean waist change at 72 weeks	−18.4 cm	−13.0 cm
Most common trial side effects	Mainly gastrointestinal; most were mild to moderate and occurred during dose escalation	Mainly gastrointestinal; most were mild to moderate and occurred during dose escalation
Familiar brand context	Active ingredient in Mounjaro and Zepbound	Active ingredient in Ozempic and Wegovy
What the trial establishes	Greater average weight and waist reduction in the studied adults without diabetes	Effective weight reduction in the same trial population, with a smaller mean reduction than tirzepatide
What the trial does not establish	Superiority for every patient or equivalence of another tirzepatide product	Inferiority for every outcome, every patient or every semaglutide formulation

Does this mean tirzepatide is always “better”?

No. SURMOUNT-5 supports a precise statement: tirzepatide produced greater average weight reduction than semaglutide after 72 weeks in adults with obesity, or overweight and a related complication, without type 2 diabetes, at the studied maximum tolerated doses.

Treatment choice is broader than one endpoint. A clinician may consider diabetes status, cardiovascular disease, kidney disease, liver disease, diabetic retinopathy, gallbladder or pancreatic history, pregnancy plans, other medicines, likely adherence, local availability and the approved indication of the exact product.

Current Wegovy labelling includes reduction of major cardiovascular events in certain adults with established cardiovascular disease and overweight or obesity. Current Zepbound labelling includes treatment of moderate-to-severe obstructive sleep apnoea in adults with obesity.³⁴ Those label-specific indications were not compared in SURMOUNT-5.

Side effects and important safety context

The most common adverse effects with both medicines are gastrointestinal, including nausea, diarrhoea, vomiting, constipation, abdominal pain and indigestion. Symptoms often occur during dose escalation, which is one reason gradual titration and clinical follow-up matter. It would be inaccurate to promise that either medicine has “fewer side effects” for every patient.

Current regulator labels for both medicines include a boxed warning about thyroid C-cell tumours observed in rodents; the relevance to humans is unknown. The medicines are contraindicated in people with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, and in people with a serious hypersensitivity to the relevant medicine or ingredients. Labels also address acute pancreatitis, gallbladder disease, severe gastrointestinal reactions, dehydration-related kidney injury, hypoglycaemia when used with certain diabetes medicines, and aspiration risk around anaesthesia or deep sedation.³⁴

Weight-loss treatment is not recommended during pregnancy. Anyone who is pregnant, planning pregnancy, breastfeeding, preparing for surgery, or taking insulin or a sulfonylurea should discuss the specific risks and timing with a qualified clinician. Current labels do not recommend combining tirzepatide with another tirzepatide-containing product or any GLP-1 receptor agonist, or combining semaglutide with another semaglutide-containing product or any GLP-1 receptor agonist.

Seek urgent medical care for severe or persistent abdominal pain, symptoms of a serious allergic reaction, or severe vomiting or diarrhoea with signs of dehydration.

What does this evidence say about TYZEPA?

According to its package presentation, TYZEPA is presented as a tirzepatide product. TYZEPA was not the product tested in SURMOUNT-5. The trial therefore cannot prove TYZEPA-specific bioequivalence, device performance, manufacturing quality, stability, effectiveness, safety or interchangeability with Mounjaro or Zepbound.

Before using any imported medicine in Pakistan, patients and clinicians should verify the exact manufacturer, sealed packaging, batch and expiry details, storage history, cold-chain integrity, supplied leaflet, local authorization or import status where applicable, and a valid prescription. Read the authenticity and storage checklist for Pakistan. Never start, switch or increase a dose based only on an online comparison.

Limitations of the comparison

SURMOUNT-5 was open-label, so participants and investigators knew which medicine was assigned. It was sponsored by Eli Lilly, the manufacturer of tirzepatide. Participants did not have type 2 diabetes, treatment lasted 72 weeks, and the sites were in the United States and Puerto Rico rather than Pakistan.¹²

The study compared particular injectable doses alongside lifestyle counselling. It did not compare every approved formulation, long-term outcome or locally available brand. Long-term treatment decisions still require individual assessment and monitoring beyond a headline percentage.

For a broader discussion of obesity, insulin resistance and metabolic risk, read the weight and metabolic health guide for Pakistan.

Questions patients ask

Clear answers, with limits.

Which produced more weight loss: tirzepatide or semaglutide?

In SURMOUNT-5, tirzepatide produced the greater average weight reduction at 72 weeks: 20.2% versus 13.7% with semaglutide. That result applies to the studied population and doses and is not an individual guarantee.

Is TYZEPA the same as Mounjaro?

Both packages identify tirzepatide as the active ingredient, but they are different branded products from different manufacturers. A shared active-ingredient name does not prove identical formulation, device, regulatory review, quality controls, storage history or clinical performance. SURMOUNT-5 did not test TYZEPA.

Are Mounjaro and Ozempic the products compared in SURMOUNT-5?

The study compared tirzepatide with semaglutide at obesity-treatment doses. For clear United States obesity-label context, the corresponding brands are Zepbound and Wegovy. Mounjaro and Ozempic are familiar brands of the same respective molecules but carry separate labels and dosing for type 2 diabetes.

Which medicine has fewer side effects?

There is no honest universal answer. Gastrointestinal effects were the most common with both medicines in SURMOUNT-5. Personal tolerability, dose escalation, coexisting conditions and other medicines can change the risk.

Can I switch from semaglutide to tirzepatide myself?

No. There is no safe one-to-one dose conversion for self-directed switching. A clinician should review the indication, current dose, timing of the last injection, adverse effects, glucose-lowering medicines, pregnancy plans and the exact replacement product.

Is this page medical advice or a prescription?

No. It is educational information. Tirzepatide and semaglutide are prescription medicines and require an individualized clinical assessment.

Primary references

Sources behind this guide.

Sources were last fact checked on 24 September 2026. International labels and studies provide context; they do not establish the regulatory status, quality or performance of a different product in Pakistan.